This invention relates to a method and apparatus for printing films housed in cartridges.
One known photographic printing apparatus for printing color images on films onto photosensitive material has a scanner unit, a printing/exposure means and a film carrier. The scanner unit optically reads printing conditions such as image densities from films. According to the data on printing conditions, the density of light from a light source is adjusted with a light adjustment filter for one of the three primary colors of light, that is, red, green and blue. The adjusted light is projected on a film to print its images onto a photosensitive material.
Light from another light source than the one for the printing/exposure means is projected on the scanner unit to allow an optical sensor to read the image information of the film. The image information is used to determine printing conditions, which are sent to the printing/exposure means in the form of electric signals.
After reading the image information, the film is sent to the printing/exposure means by the film carrier and printed. Printing conditions are determined for each frame of a film using an average value of the image densities in all the frames of the film as a reference.
In one conventional arrangement, films are manually inserted one by one into the printing apparatus. In another arrangement, a plurality of films are spliced together at their ends and wound on a reel. The spliced films are automatically fed into the printing apparatus through the film supply unit.
The image information of the films inserted in the printing apparatus is read by the scanner unit provided along the feed path in the film carrier. Films are then printed under conditions determined based on the image information. Generally speaking, the time needed for reading the image density and determining the printing conditions is shorter than the time for printing.
Because of such differences in processing time, while one film is being printed, the subsequent film is kept in a stand-by position without reading its image density. After the printing of the first film has finished, while the image density of the subsequent film is being read, no printing is done.
In such an arrangement, it is impossible to process a plurality of films with high efficiency. One possible solution to this problem is to drive the scanner unit and the printing/exposure means independently of each other and to further provide a loop portion therebetween to adjust the feed of films.
By feeding a plurality of films spliced together and wound on a reel into such a printing apparatus, it is possible to improve the processing speed and efficiency considerably.
One problem of this arrangement is that only one reel for supplying film can be attached to the printing apparatus at a time. Namely, it is impossible to process a plurality of films wound on one plurality of reels at a time. Thus, the film processing speed is limited. In this regard, this arrangement has still room for improvement.